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CHEMISTRY
Yu. A. ARBUZOV, E. M. KLIMOV and E. I. KLIMOVA
DIENE SYNTHESIS WITH GLYOXYLIC ACID ESTERS
(Presented by Academician A. E. Arbuzov on 31 VII 1961)
Diene syntheses with carbonyl compounds leading to the formation of derivatives of 5,6-dihydro-1,2-pyran have been studied very little. Reactions have been carried out of 2-methylpentadiene with formaldehyde (¹), of 2,3-dimethylbutadiene, isoprene, and piperylene with chloral (²), of 2,3-dimethylbutadiene with chloroacetaldehyde (³), and of butadiene and 2,3-dimethylbutadiene with cyanic carbonyl and diethyl mesoxalate (⁴).
We found that 1,3-dienes readily react with glyoxylic acid esters or their hemiacetals to form the corresponding derivatives of 5,6-dihydro-1,2-pyran. In the condensation of butadiene and 2,3-dimethylbutadiene with ethyl glyoxylate and n-butyl glyoxylate or their hemiacetals, the corresponding adducts I—IV were obtained:
\[ \begin{array}{c} \text{[structural scheme]}\\ \end{array} \qquad \begin{array}{ll} \text{I.} & R = H,\quad R' = C_2H_5\\ \text{II.} & R = H,\quad R' = n\text{-}C_4H_9\\ \text{III.} & R = CH_3,\quad R' = C_2H_5\\ \text{IV.} & R = CH_3,\quad R' = n\text{-}C_4H_9 \end{array} \]
In the reaction of 1,3-cyclohexadiene with the n-butyl hemiacetal of n-butyl glyoxylate, adduct V was obtained:
\[ \begin{array}{c} \text{[structural scheme]} \qquad V \end{array} \]
The structure of adducts I—V was established as follows. On acid hydrolysis of adducts I and II* 5,6-dihydro-1,2-pyran-6-carboxylic acid VI was obtained, catalytic hydrogenation of which led to tetrahydropyran-2-carboxylic acid VII. On alkaline hydrolysis of adducts III and IV, 3,4-dimethyl-5,6-dihydro-1,2-pyran-6-carboxylic acid VIII was formed; catalytic reduction of this acid gave 4,5-dimethyltetrahydropyran-2-carboxylic acid IX. Catalytic reduction of adduct V gave the dihydro derivative X, acid hydrolysis of which gave 3,6-endoethylenetetrahydropyran-2-carboxylic acid XI.
Experimental Part
Condensation of ethyl glyoxylate and n-butyl glyoxylate with butadiene
Ethyl ester of 5,6-dihydro-1,2-pyran-6-carboxylic acid (I). A mixture of 14.8 g (0.1 g-mol) of the ethyl hemiacetal of ethyl glyoxylate, 10.8 g (0.2 g-mol) of butadiene, and 0.3 g of hydroquinone was heated in an autoclave at 120—130° for 2.5 h. Obtained 7.2 g (46%)
* We were unable to isolate these adducts in analytically pure form.
colorless liquid with b.p. 57–58°/2 mm, \(n_D^{20}\) 1.4506, \(d_4^{20}\) 1.0692. \(MR\) 39.30. Calculated 39.77.
\[ \begin{aligned} &\text{Found, \%: } && \mathrm{C}\ 60.26,\ 60.40;\quad \mathrm{H}\ 7.92,\ 7.82\\ &\mathrm{C_8H_{12}O_3}.\ \text{Calculated, \%: } && \mathrm{C}\ 61.52;\quad \mathrm{H}\ 7.75 \end{aligned} \]
5,6-Dihydro-1,2-pyran-6-carboxylic acid (VI). A mixture of 3.12 g (0.02 g-mol) of ester (I), 30 ml of acetic acid, and 12 ml of \(2N\) hydrochloric acid was boiled for 1.5 h. This gave 1.85 g (72%) of acid (VI) with b.p. 96–98°/2.5 mm, \(n_D^{20}\) 1.4817, \(d_4^{20}\) 1.2151. \(MR\) 30.04. Calculated 30.42. p-Bromophenacyl ester: m.p. 126–128° (from ethanol).
Literature data: b.p. 60°/0.005 mm, \(n_D^{20}\) 1.4831, \(d_4^{20}\) 1.218; m.p. of the p-bromophenacyl ester 127–128° \((^4)\).
Tetrahydropyran-2-carboxylic acid (VII). 8.5 g (0.066 g-mol) of acid (VI) in 65 ml of ethanol was hydrogenated in the presence of 0.5 g of palladium oxide. This gave 7.0 g (81%) of a colorless liquid with b.p. 76–78°/2 mm, \(n_D^{20}\) 1.4595, \(d_4^{20}\) 1.1400. \(MR\) 31.24. Calculated 30.89. p-Bromophenacyl ester: m.p. 100–101° (from ethanol).
Literature data: b.p. 110.5°/5 mm, \(n_D^{20}\) 1.4665 \((^5)\), b.p. 100°/2.3 mm, \(n_D^{20}\) 1.4618; m.p. of the p-bromophenacyl ester 101–102° \((^4)\).
The n-butyl ester of 5,6-dihydro-1,2-pyran-6-carboxylic acid (II). Experiment 1. A mixture of 13.0 g (0.1 g-mol) of n-butyl glyoxylate, 10.8 g (0.2 g-mol) of butadiene, and 0.5 g of hydroquinone was heated in an autoclave at 120–130° for 3 h. This gave 7.5 g (41%) of a colorless liquid with b.p. 90–91°/2 mm, \(n_D^{20}\) 1.4552, \(d_4^{20}\) 1.0292. \(MR\) 48.58. Calculated 49.01.
\[ \begin{aligned} &\text{Found, \%: } && \mathrm{C}\ 64.28,\ 64.27;\quad \mathrm{H}\ 8.78,\ 8.68\\ &\mathrm{C_{10}H_{16}O_3}.\ \text{Calculated, \%: } && \mathrm{C}\ 65.19;\quad \mathrm{H}\ 8.75 \end{aligned} \]
Experiment 2. A mixture of 15.3 g (0.075 g-mol) of the n-butyl hemiacetal of n-butyl glyoxylate, 10.8 g (0.2 g-mol) of butadiene, and 0.5 g of hydroquinone was heated in an autoclave at 120–130° for 3 h. This gave 6.5 g (47%) of adduct (II) with b.p. 92–95°/2.5 mm and \(n_D^{20}\) 1.4548. Saponification of 14.3 g (0.078 g-mol) of ester (II) with a mixture of acetic acid (100 ml) and \(2N\) hydrochloric acid (50 ml) gave 7.5 g (75%) of acid (VI): b.p. 101°/2 mm, \(n_D^{20}\) 1.4825, \(d_4^{20}\) 1.2137. \(MR\) 30.12. Calculated 30.42. p-Bromophenacyl ester: m.p. 126–128° (from ethanol).
Condensation of ethyl glyoxylate and n-butyl glyoxylate with 2,3-dimethylbutadiene
Ethyl ester of 3,4-dimethyl-5,6-dihydro-1,2-pyran-6-carboxylic acid (III). A mixture of 14.8 g (0.1 g-mol) of the ethyl hemiacetal of ethyl glyoxylate, 10.0 g (0.12 g-mol) of 2,3-dimethylbutadiene, and 0.5 g of hydroquinone was heated in an autoclave at 120–130° for 3 h. This gave 14.2 g (77%) of a colorless liquid with b.p. 102–104°/2 mm, \(n_D^{20}\) 1.4662, \(d_4^{20}\) 1.0397. \(MR\) 49.09. Calculated 49.01.
\[ \begin{aligned} &\text{Found, \%: } && \mathrm{C}\ 65.07,\ 65.31;\quad \mathrm{H}\ 8.70,\ 8.85\\ &\mathrm{C_{10}H_{16}O_3}.\ \text{Calculated, \%: } && \mathrm{C}\ 65.19;\quad \mathrm{H}\ 8.75 \end{aligned} \]
3,4-Dimethyl-5,6-dihydro-1,2-pyran-6-carboxylic acid (VIII). 3.68 g (0.02 g-mol) of ester (III) was mixed with 15 ml of a 10% ethanolic KOH solution. The precipitated potassium salt was filtered off and dissolved in 10 ml of \(2N\) HCl with heating. On cooling the mixture, colorless crystals of acid (VIII) separated, m.p. 86–87° (from \(\mathrm{CCl_4}\)). Yield 2.38 g (76%). Literature data: m.p. 85–86° \((^4)\).
4,5-Dimethyltetrahydropyran-2-carboxylic acid (IX). 9.0 g (0.058 mole) of acid (VIII) in 90 ml of ethanol was reduced in the presence of 0.5 g of platinum oxide. This gave 7.9 g (87%) of a colorless liquid with b.p. 106–107°/3 mm, \(n_D^{20}\) 1.4670, \(d_4^{20}\) 1.0918. \(MR\) 40.20. Calculated 40.12. Literature data: b.p. 137–138°/10 mm, \(n_D^{20}\) 1.4650, \(d_4^{20}\) 1.091 (4).
n-Butyl ester of 3,4-dimethyl-5,6-dihydro-1,2-pyran-6-carboxylic acid (IV). A mixture of 13.0 g (0.1 mole) of n-butyl glyoxylate, 10.0 g (0.12 mole) of 2,3-dimethylbutadiene, and 0.5 g of hydroquinone was heated in an autoclave at 120–130° for 3 hours. This gave 14.9 g (70%) of a colorless liquid with b.p. 100–101°/1 mm, \(n_D^{20}\) 1.4660, \(d_4^{20}\) 1.0049. \(MR\) 58.51. Calculated 58.25.
\[ \mathrm{C}_{12}\mathrm{H}_{20}\mathrm{O}_3. \quad \begin{array}{ll} \text{Found, \%:} & \mathrm{C}\ 67.81,\ 67.88;\quad \mathrm{H}\ 9.40,\ 9.46\\ \text{Calculated, \%:} & \mathrm{C}\ 67.89;\quad \mathrm{H}\ 9.50 \end{array} \]
On saponification of 4.24 g (0.02 mole) of ester (IV) with a 10% ethanolic solution of KOH, 2.37 g (76%) of acid (VIII) was obtained, m.p. 86–87° (from \(\mathrm{CCl}_4\)).
Condensation of n-butyl glyoxylate with 1,3-cyclohexadiene
n-Butyl ester of 2,5-endoethylene-5,6-dihydro-1,2-pyran-6-carboxylic acid (V). A mixture of 20.4 g (0.1 mole) of the n-butyl hemiacetal of n-butyl glyoxylate and 12.0 g (0.15 mole) of 1,3-cyclohexadiene was heated in a sealed ampoule in the vapors of boiling anisole (b.p. 155°) for 3 hours. This gave 14.5 g (69%) of a colorless liquid with b.p. 105–106°/1 mm, \(n_D^{20}\) 1.4750, \(d_4^{20}\) 1.0575. \(MR\) 55.98. Calculated 56.05.
\[ \mathrm{C}_{12}\mathrm{H}_{18}\mathrm{O}_3. \quad \begin{array}{ll} \text{Found, \%:} & \mathrm{C}\ 68.28,\ 68.15;\quad \mathrm{H}\ 8.81,\ 8.79\\ \text{Calculated, \%:} & \mathrm{C}\ 68.54;\quad \mathrm{H}\ 8.69 \end{array} \]
n-Butyl ester of 3,6-endoethylenetetrahydropyran-2-carboxylic acid (X). 14.0 g (0.067 mole) of ester (V) in 60 ml of ethanol was hydrogenated in the presence of 0.2 g of platinum oxide. This gave 13.0 g (92%) of a colorless liquid with b.p. 105–107°/2 mm, \(n_D^{20}\) 1.4690, \(d_4^{20}\) 1.0397. \(MR\) 56.85. Calculated 56.51.
\[ \mathrm{C}_{12}\mathrm{H}_{20}\mathrm{O}_3. \quad \begin{array}{ll} \text{Found, \%:} & \mathrm{C}\ 67.53,\ 67.57;\quad \mathrm{H}\ 9.22,\ 9.36\\ \text{Calculated, \%:} & \mathrm{C}\ 67.89;\quad \mathrm{H}\ 9.50 \end{array} \]
3,6-Endoethylenetetrahydropyran-2-carboxylic acid (XI). A mixture of 10.6 g (0.05 mole) of ester (X), 100 ml of \(\mathrm{CH_3COOH}\), and 10 ml of 10% HCl was boiled for 1 hour. This gave 6.9 g (88%) of a colorless liquid with b.p. 119–120°/2 mm, \(n_D^{20}\) 1.4950, \(d_4^{20}\) 1.2034. \(MR\) 37.85. Calculated 37.92.
\[ \mathrm{C}_{8}\mathrm{H}_{12}\mathrm{O}_3. \quad \begin{array}{ll} \text{Found, \%:} & \mathrm{C}\ 61.50,\ 61.53;\quad \mathrm{H}\ 7.88,\ 7.74\\ \text{Calculated, \%:} & \mathrm{C}\ 61.52;\quad \mathrm{H}\ 7.75 \end{array} \]
Moscow State University
named after M. V. Lomonosov
Received
28 VII 1961
REFERENCES
- T. L. Gresham, T. R. Steadman, J. Am. Chem. Soc., 71, 737 (1949).
- W. J. Dale, A. J. Sisti, J. Am. Chem. Soc., 76, 81 (1954).
- W. J. Dale, A. J. Sisti, J. Org. Chem., 22, 449 (1957).
- O. Achmatowicz, A. Zamojski, Croat. Chem. Acta, 29, 269 (1957).
- R. R. Whetstone, S. A. Ballard, J. Am. Chem. Soc., 73, 5280 (1951).